Open to opportunities

Денис Варлашин

@0005181

Message

I build reliable Java backend services for real-time mobility, fintech, and high-volume distributed systems.

Germany

Message

What I'm looking for

I'm open to remote and freelance opportunities where I can build reliable backend systems, improve observability and cost efficiency, mentor engineers, and collaborate with product owners and analysts on business-focused solutions.

At Flix, I build and maintain mission-critical backend services for passenger transportation, including real-time trip updates, passenger reassignment, access control, and reliability improvements.

I reduced infrastructure spend by about 20% through distributed caching, delivered a WebSocket channel for fresher customer-facing trip data, and built Azure test-user provisioning for automated scenarios. I also use AI in daily backend work to accelerate refactoring, testing, architecture exploration, and infrastructure cost decisions.

Previously, at Triple A Internetshops, I led four backend developers while building services for an AI-powered skincare app, including recommendations, product matching, and an adaptive video processing and delivery pipeline on AWS.

Across Flix, Sixt, SmartTrader, DataArt, Luxoft, and Deutsche Bank projects, I’ve worked with monoliths and microservices, SQL and NoSQL data stores, event-driven systems, and developer-friendly APIs. I enjoy improving observability, reliability, technical debt practices, and the engineers around me.

Experience

Work history, roles, and key accomplishments

Current

Senior Java Developer

Current

Flix

Jun 2022 - Present (4 years 2 months)

Building and maintaining mission-critical backend services for passenger transportation. Focus areas: real-time trip updates, reassigning passengers between rides, access control, engineering quality, reliability, and cost efficiency.

✅ Key contributions
● I’m actively bringing AI into my day-to-day backend work — using it to speed up repetitive tasks, improve and refactor code, generate test dat

Java AWS MongoDB PostgreSQL Hazelcast Snowflake Microservices Kubernetes Redis Spring Framework Elasticsearch

Team Lead/Senior Java Developer

Triple A Internetshops GmbH

Apr 2021 - Jun 2022 (1 year 2 months)

Built backend services for an AI-powered skincare app that detects skin issues and provides personalized recommendations and product matching. Implemented the core business logic and a content management backend for expert content, including video storage, transcoding, and efficient delivery with quality adaptation for different network conditions.

✅ Key contributions
● Led a team of 4 back-end d

Java Spring Framework Quarkus PostgreSQL Redis AWS Lambda Microservices Kubernetes SQL Unit Testing JSON CI CD Grafana Agile

Senior Java Developer

SmartTrader

Aug 2020 - Apr 2021 (8 months)

Worked as Senior Java Developer at SmartTrader.

Java Oracle Spring Framework

Java Developer

DataArt

Nov 2019 - Aug 2020 (9 months)

NDA

Java Spring Framework PostgreSQL Agile

Java Developer

Sixt

Jul 2018 - Nov 2019 (1 year 4 months)

Worked as Java Developer at Sixt.

Camunda Microservices PostgreSQL Kubernetes

Junior Java Developer (Deutsche bank)

Luxoft

Aug 2016 - Jul 2018 (1 year 11 months)

Worked as Junior Java Developer (Deutsche bank) at Luxoft.

Telecommunication Engineer

Luxoft

Oct 2012 - Aug 2016 (3 years 10 months)

Worked as Telecommunication Engineer at Luxoft.

Asterisk Linux Avaya

System Administrator

Russian Standard Bank Ukraine

Nov 2011 - Jun 2012 (7 months)

Worked as System Administrator at Russian Standard Bank Ukraine.

Windows Linux Дизайнер продукту ERP

Education

Degrees, certifications, and relevant coursework

Codecademy

HTML & CSS, Bash

2014 - 2016

Codecademy is a team of hackers working hard to build a better way for anyone to teach, and learn, how to code. We're determined to succeed in realizing our mision to turn a world of tech consumers into one of empowered builders. We're backed by some great people, including: Union Square Ventures, O'Reilly, SV Angel, Thrive Capital, Index Ventures, CrunchFund, Collaborative Fund, Founder Collectiv

CodeFire

Java Trainee, Java

2015 - 2015

3 months / 48 hours

Introduction to Java Virtual Machine
The basic structure of the Java language
One-dimensional and n-dimensional arrays
Object-oriented approach
Java Collections Framework
Working with the file system
Multithreaded Programming
Create network applications
Graphical User Interface (Swing)
Job application database

CodeFire

Java Junior, Java

2015 - 2015

2 months / 32 hours

Creating a Web interface (html / css)
Interactivity (JavaScript / JQuery / Twitter Bootstrap)
Browse Server for Web applications
Server Pages Java (JSP)
Standard Tag Library (JSTL)
Server components (Servlets)
The pattern of MVC (Model-View-Controller)
Filters and server events
The implementation of web-services in Java
Training GIT